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PhD Thesis
PhD thesis director name: Stéphane BASA
Email: sté[email protected]
Phone number: +6 37 21 61 20
Co-director: Sandra SAVAGLIO (Physics Department, University of Calabria, Italy)
PhD title: Exploring the dawn of the Universe with the Sino-French SVOM
mission
Subject description (1 page max.):
Gamma Ray Bursts (GRBs), the most powerful explosions since the formation of
our Universe, are unique cosmic events. Lasting from a few milliseconds to
several minutes, the radiation emitted in this interval is equivalent to that of the
Sun over its entire life. They are hundreds of times brighter than a typical
supernova, the ultimate end of a massive star.
Due to the extreme luminosity of their multi-wavelength emissions, they are now
considered as one of the best ways to probe the dawn of the Universe. The
tremendous luminosity of both the prompt gamma-ray emission, and the X-ray
and optical afterglow indicates that GRBs should be visible out to large distances,
when the universe was only a few hundreds million years old (redshift z > 10).
France and China just agreed to co-build the SVOM mission, dedicated to the
detection and observation of GRBs (launch date: 2021). This mission is the proud
successor (and, the moment, the only one approved) to the SWIFT mission, and
will provide a systematic study of all types of bursts (e.g., short or distant). It
has been carefully designed to allow a very high scientific return, thanks in
particular to the organization of an ambitious multi-wavelength follow-up. The
latter is based on a complex system involving a network of 1-m telescopes,
which automatically and quickly follow the alerts, and larger diameter telescopes
(e.g., VLT, ALMA, E-ELT, JWST) for very deep observations.
The student will actively work on the implementation of the system, in particular
by optimizing the search for the most distant bursts (beyond z = 5). He/she will
have to develop the system allowing the identification of the farthest GRBs with
the network of 1-m robotic telescopes and to implement a system allowing an
efficient triggering of the largest telescopes. He/she will work in close
collaboration with CPPM, IRAP and CEA in France, NAOC in China, University of
Calabria in Italy, etc.
Moreover, to have a deep knowledge of the scientific needs, student will also
conduct studies on the galaxies hosting the GRB. Indeed GRBs offer a unique
opportunity to localize galaxies independently of their optical/NIR luminosities,
and, thus, single out a population, which is hard to detect with traditional means.
This approach has shown in the past large consequences on our understanding of
galaxy formation and evolution. The student will work on multi-wavelength
observations, from radio to optical domains from the latest far-infrared, submillimeter and radio telescopes (e.g., SCUBA-2, ALMA). The estimated Spectral
Energy Distribution (SED) of the sample of hundreds of GRB host galaxies will be
compared to synthetic models to derive, for each galaxy, key environmental
features, such as star-formation history, stellar age, metal content, stellar mass,
dust mass and temperature. It will be then possible to investigate how the
UV/optical and radio derived SFRs can be reconciled.
The student will have to actively participate to the preparation of observational
proposals, and lead observations, data processing and final scientific analysis.
He/she will lead some of the publications associated with these observations and
other data publicly available. He/she will then play a key role during all necessary
steps, making him/her a professional astronomer. He/she will work with two
experienced teams, LAM in Marseille (France) and University of Calabria (Italy).
The student will have to spend a fraction of his/her time in Italy.
This Ph'D is proposed in the framework of the SVOM mission and of the European
Research Network, GDRE, Exploring the Dawn of the Universe with Gamma-Ray
Bursts.
Références bibliographiques:
• L. Hunt et al. New light on gamma−ray burst host galaxies with Herschel,
Astronomy & Astrophysics, Volume 565, id.A112, 2014
•
M. Michalowski et al. Spatially−resolved dust properties of the GRB
980425 host galaxy, Astronomy & Astrophysics, Volume 562, id.A70, 2014
• P. Schady et al., Herschel observations of gamma-ray burst host galaxies:
implications for the topology of the dusty interstellar medium, MNRAS,
2014
•
S. Basa et al., Constraining the nature of the most distant Gamma-Ray
Burst host galaxies, A&A 2012
•
S. Savaglio et al., The Galaxy Population Hosting Gamma-Ray Bursts, ApJ,
2009